Find the area of the triangle formed by the lines `y-x=0,x+y=0`and `x-k=0`.

Explanation

Equation of line 1,`L_1->y-x = 0=> x= y->(1)`

Equation of line 2,`L_2->x+y = 0=> x = -y->(2)`

Equation of line 3,`L_3->x-k = 0=> x = k->(3)`

Now, if we draw these lines, it will form a triangle with vertices, `(0,0),(k,k),(k,-k)`.

Please refer to video for the diagram.

Now, from the diagram, we can see that,

Base of triangle `=2k`

Altitude of triangle ` = k`

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